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The 2-Stroke Garage => Turning Wrenches => Topic started by: rearwheelslider on March 15, 2024, 02:44:40 PM

Title: Cylinder wear after full rebuild RD400F
Post by: rearwheelslider on March 15, 2024, 02:44:40 PM
Hello all, I have been riding the RD400F after the restoration for aprox 150 miles. I checked the head torques after the first run and they were very very loose. Highly recommend to check this on the regular!I stuck a bore scope in the cylinders to find good burn pattern on the pistons and the jetting isnt too far off based on ridability and reading the plugs.However, there are signs of wear on the cylinders, especially above the exhaust port. I am used to plated cylinders showing very little wear after 200 hours of hard use, so this is a bit alarming. The bike sounds tight and I always warm her up before getting on the gas. Would you say this wear is normal for a non plated cylider?
Title: Re: Cylinder wear after full rebuild RD400F
Post by: m in sc on March 15, 2024, 03:27:07 PM
might have had a slight head gasket leak. id check again in 50 miles,see if it changed
Title: Re: Cylinder wear after full rebuild RD400F
Post by: 1976RD400C on March 16, 2024, 07:06:18 AM
Looks like maybe the ports could have been chamfered a bit more but I would worry about that little bit of scuffing.
Edit: wouldn't worry, looks real light
Title: Re: Cylinder wear after full rebuild RD400F
Post by: m in sc on March 16, 2024, 09:10:52 AM
yeah., its hard to tell by a pic. how deep was that scuffing?

Title: Re: Cylinder wear after full rebuild RD400F
Post by: 85RZwade on March 16, 2024, 10:43:32 AM
Off topic, but great looking bike!
Title: Re: Cylinder wear after full rebuild RD400F
Post by: rearwheelslider on March 19, 2024, 11:52:25 AM
Quote from: m in sc on March 16, 2024, 09:10:52 AMyeah., its hard to tell by a pic. how deep was that scuffing?


It was not deep, crosshatch still present under the vertical 'scuffing'.  :gentleman:
Title: Re: Cylinder wear after full rebuild RD400F
Post by: rearwheelslider on March 19, 2024, 11:52:50 AM
Quote from: 85RZwade on March 16, 2024, 10:43:32 AMOff topic, but great looking bike!
Thank you brotha! Love riding this thing.